2.2.1 Replying to Mail

To compose a reply to a message, use the r (mh-reply)
command. If you supply a prefix argument (as in C-u r), the
message you are replying to is inserted in your reply after having first
been run through mhl with the format file `mhl.reply'. See
mhl(1) to see how you can modify the default `mhl.reply'
file.

When you reply to a message, you are first prompted with `Reply to
whom?'. You have several choices here.

ResponseReply Goes Tofrom The person who sent the message. This is the default,
so RET is sufficient.
to Replies to the sender, plus all recipients in the
`To:' header field.
allcc Forms a reply to the sender, plus all recipients.

Depending on your answer, repl is given a different argument to
form your reply. Specifically, a choice of from or none at all
runs repl -nocc all, and a choice of to runs repl -cc
to. Finally, either cc or all runs repl -cc all
-nocc me.

Two windows are then created. One window contains the message to which
you are replying. Your draft, in MH-Letter mode (described in
2.3 Editing a Draft), is in the other window.

If you wish to customize the header or other parts of the reply draft,
please see repl(1) and mh-format(5).